1. Field of the Invention
The present invention relates to a production method and a production apparatus for a rotor which is produced by combining a slot insulator and a coil bar to a rotor core.
2. Description of Related Art
Japanese Patent Application No. 7-326983 (U.S. patent application Ser. No. 08/574,033) discloses a method of integrating or assembling coil bars (lower layer coil bars and upper layer coil bars) each in a channel-like shape having a linear coil trunk and a pair of coil arms and slot insulators (lower layer slot insulators and upper layer slot insulators) for insulating the coil trunks inserted into slots of a rotor (armature) core from the armature core, to the armature core.
However, according to the above integrating method, there poses the following problem in order to insert the coil trunks of the coil bars into the slots after inserting the slot insulators into the slots of the armature core.
That is, the slot insulators are not positioned in the axial direction in respect of the slots of the armature core and therefore, the slot insulators may be shifted in the axial direction in the slots. In this case, for example, in respect of the lower layer slot insulator, the length in the axial direction is substantially equal to the length of the slot (length of armature core in the axial direction) plus a thickness of a pair of disk-like inner side insulators and therefore, when the lower layer slot insulator is shifted in the axial direction at inside of the slot, one end of the lower layer slot insulator is projected from either of end faces of the pair of disk-like inner side insulators arranged at both end faces of the armature core. When the lower layer coil bar is made to be inserted into the slot under this state, as shown in FIG. 46, a coil trunk 8b of a lower layer coil bar 8 may interfere with the projected one end of the lower layer slot insulator 4 and a coil arm 8a may not be inserted into a slot 3a with certainty.
Particularly, when the length of the lower layer slot insulator in the axial direction is set to be slightly larger than the length of the lower layer coil trunk, the influence by the shift of the lower layer slot insulator in the axial direction becomes significant. As a result, when, for example, the lower layer slot insulator is produced by a soft material in a thin film shape, it is conceivable that the lower layer slot insulator may be deformed or destructed easily by the interference with the coil arm.
Further, when the slot insulator is integrated to shift in the axial direction in respect of the slot, although one end of the slot insulator in the axial direction is projected from the end face of the armature core, the other end of the slot insulator is recessed from the end face of the armature core and therefore, the wall face of the slot is exposed and the insulation in respect of the coil trunk cannot be ensured.
Further, although a method of positioning the slot insulator in the axial direction in respect of the slot by arranging a positioning member on the side of the end face of the armature core and bringing one end of the slot insulator in contact with the positioning member, is possible, when the slot insulator is produced by a soft material in a thin film shape, the rigidity of the slot insulator is deficient and therefore, the accurate positioning may not be carried out since the side of the one end of the slot insulator which is brought into contact with the positioning member is deformed. When the coil trunk is inserted into the slot under this state, the coil arm interferes with the deformed portion of the slot insulator and the coil trunk cannot be integrated into the slot with certainty. Further, when the slot insulator is shifted in the axial direction in accordance with the deformation of the one end side, the other end side of the slot insulator is recessed into the slot and the wall face of the slot is exposed and therefore, the coil trunk may not be insulated from the armature core with certainty.